The article deals with the unprecedented collision in the history of the World War II, when former allies - Britain and France - aimed weapons upon each other in summer of 1940. After the defeat of France the main units of the French Navy were sent to North and West African Ports. Winston Churchill wanted to prevent falling the French warships into German or Italian hands at any cost. In accordance with his orders Force H under command of Admiral James Somerville destroyed the most powerful French unit at Oran on July 3, 1940. At the same day Admiral Cunningham disarmed French squadron at Alexandria without bloodshed. Cunningham's success at Alexandria set Churchill's action at Oran in a different moral and political perspective.